The invention relates to a product designed for hot gas admission with a coating, particularly a gas turbine blade. The invention furthermore relates to a process for producing a coating for a product designed for hot gas admission.
The article entitled xe2x80x9cDiffusion barrier coatings with active bonding, designed for gas turbine blades,xe2x80x9d by O. Knotek, E. Lugscheider, F. Lxc3x6ffler, W. Beele, in the xe2x80x9cProceedings of the 21st International Conference on Metallurgical Coatings and thin Films,xe2x80x9d San Diego, Calif., USA, Apr. 25-29, 1994, describes a diffusion barrier coating for a gas turbine blade. A gas turbine blade frequently has an oxidation or corrosion protective coating applied to a base material, typically a superalloy. Due to diffusion processes, brittle phases may form in the coating, which impairs the life of the gas turbine blade. The goal of the research is to develop a diffusion barrier between the base material and the coating, which simultaneously ensures good bonding of the coating to the base material. This is achieved by a chromium aluminum oxide nitride system (Crxe2x80x94Alxe2x80x94Oxe2x80x94N).
The object of the invention is to define a product designed for hot gas admission, which is provided with an improved coating with respect to its long-term stability. A further object of the invention is to define a process to produce a coating for a product designed for hot gas admission.
According to the invention, the product-related object is attained by a product designed for hot gas admission made of a base material to which a coating is applied comprising:
a) a protective MCrAlY coating comprising
at least one metal selected from the group (iron, cobalt, nickel), abbreviated as M;
chromium (Cr) with a content of at least 15 wt-%, particularly at least 20 wt-%;
aluminum (Al) and
yttrium (Y) and/or hafnium and/or a metal selected from the rare earth group, particularly scandium, lanthanum, or cerium;
b) an oxide layer, particularly with aluminum oxide and/or chromium oxide;
c) chromium nitride.